Leicester's England hooker George Chuter believes Cardiff Blues will have "a point to prove" in Saturday's Heineken Cup clash which could make or break Tigers' European hopes.
Leicester must beat the Blues at Welford Road to set up a Pool Four decider with Cup holders Munster in Limerick on Saturday week.
Cardiff's own European ambitions were effectively derailed by a Millennium Stadium defeat against Leicester almost three months ago - and Tigers star Chuter warned: "We expect them to come out with all guns blazing.
"They will have a point to prove after losing to us in a very tight game, and some of their Magners League form shows they can be a real threat.
"There is also the extra spice of it being an English team against a Welsh team, so we know it will be a bit special.
"Ever since we lost at home to Munster in the opening round of Heineken Cup fixtures, every game has been a must-win for us - so there is nothing new about this one.
"The Munster defeat left us with no room for manoeuvre, but it really was the big kick up the backside we needed at that time. It snapped us back into European mode, because the Heineken Cup is different from the Guinness Premiership and requires different things."
Fly-halves Andy Goode and Paul Burke look set to miss the Cardiff encounter through injury, meaning a likely start for Ian Humphreys at number 10 - while the Blues are without suspended Wales flanker Martyn Williams.
Gloucester face a fight for their Heineken Cup lives in the south of France on Friday night, with captain Marco Bortolami admitting: "We have only one chance."
A Gloucester defeat against Pool Two hosts Agen - and group favourites Leinster beating Edinburgh in Dublin on Saturday - would signal the end for Bortolami and company in Europe this season.
Gloucester, though, intend throwing everything at opponents whose shock 32-26 success on west-country soil 11 weeks ago seriously hindered the Guinness Premiership club's quarter-final ambitions.
Bortolami said: "Agen will play with big intensity, but we have everything we need to win this game.
"We have only one chance now, and I think it is the right pressure on the team. We have to perform - and we have to win."
Gloucester head coach Dean Ryan makes a solitary change from the side edged out by Sale Sharks last Saturday, with Christian Califano returning to face his former club - while James Forrester packs down in the back row just four days before he faces a Rugby Football Union disciplinary hearing, having been cited for allegedly kneeing Sale fly-half David Blair at Edgeley Park.
Pool One leaders Wasps will move to within sight of a last-eight spot if they topple Adams Park visitors Perpignan on Saturday, but Pool Five strugglers London Irish and Toulouse are playing for little more than pride at the Madejski Stadium.
Group leaders Llanelli Scarlets can secure a quarter-final slot one game inside the distance by beating Ravenhill hosts Ulster on Saturday.
"You don't win at Ravenhill by chance - you have to go there and really perform," said Llanelli's Wales wing Mark Jones.
"I honestly believe it is one of the toughest places in Europe to get a victory.
"Welsh rugby quite rightly measures itself by success in Europe - and because it has been something of a barren land for Welsh teams in recent seasons, it would be great for us and Wales to have a quarter-final qualifier."
Elsewhere on Saturday, Sale make the trip to Italy for a Pool Three appointment with Calvisano - and Castres visit Treviso in Pool One.